A group of 12 people, who all use Apple's mobile devices, are seeking damages in a case thought to be the first of its kind in the UK.
If they are successful, the landmark case could enable up to 10 million Britons to sue Google for alleged privacy breaches, reports The Sunday Times.
Google was last year found to have circumvented privacy controls in the iPhone, iPad and Mac versions of Safari in order to place advertising tracking cookies between summer 2011 and spring 2012.
Law firm Olswang, which is bringing the case, gave the example of a person running an internet search for an engagement ring, and their partner later encountering adverts for rings while browsing the web using the same device.
Users previously thought the cookies would be blocked after Google gave assurances when the situation first game to light.
Dan Tench, the lawyer behind the action at Olswang, told The Guardian: "This is the first time Google has been threatened with a group claim over privacy in the UK. It is particularly concerning how Google circumvented security settings to snoop on its users.
"One of the things about Google is that it is so ubiquitous in our lives and if that's its approach then it's quite concerning."
In August last year, Google was fined $22.5 million (£14.4m) in the US to settle charges that it violated privacy settings in the Safari browser in Apple devices.
Google's alleged actions were found to be in violation of an earlier privacy settlement (known as a commission order) between the US search giant and the US Federal Trade Commission (FTC), leading to the massive fine.
Security researchers also revealed last February that Google's DoubleClick advertising network intentionally stored cookies on user's computers without their consent.
A Facebook group called 'Safari Users Against Google's Secret Tracking' has been set up and vows to provide users with information on the alleged illegal tracking.
It says: "Google deliberately undermined protections on the Safari browser so that they could track users' internet usage and to provide personally tailored advertising based on the sites previously visited.
"There was no way to know that Google did this. In fact, they made it clear that they did not do this on the Safari browser.
"[But] it could mean for many users that surprises such as engagements, presents and holidays were destroyed when partners looked at their computers and saw display ads based on sites previously visited. There are many examples of the inappropriate consequences of such intrusion."
Members of the "informal group" have directed Olswang to bring legal action against Google, and have invited anyone who feels that they may also have been affected to join the action.
The group is understood to want compensation from Google, but the exact figure is not known. They also want Google to reveal how it used private information it allegedly obtained.